1 files changed, 127 insertions, 0 deletions
diff --git a/jcmaster.c b/jcmaster.c
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+++ b/jcmaster.c
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+/*
+ * jcmaster.c
+ *
+ * Copyright (C) 1991, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the main control for the JPEG compressor.
+ * The system-dependent (user interface) code should call jpeg_compress()
+ * after doing appropriate setup of the compress_info_struct parameter.
+ */
+
+#include "jinclude.h"
+
+
+METHODDEF void
+c_per_scan_method_selection (compress_info_ptr cinfo)
+/* Central point for per-scan method selection */
+{
+  /* Edge expansion */
+  jselexpand(cinfo);
+  /* Subsampling of pixels */
+  jselsubsample(cinfo);
+  /* MCU extraction */
+  jselcmcu(cinfo);
+}
+
+
+LOCAL void
+c_initial_method_selection (compress_info_ptr cinfo)
+/* Central point for initial method selection */
+{
+  /* Input image reading method selection is already done. */
+  /* So is output file header formatting (both are done by user interface). */
+
+  /* Gamma and color space conversion */
+  jselccolor(cinfo);
+  /* Entropy encoding: either Huffman or arithmetic coding. */
+#ifdef ARITH_CODING_SUPPORTED
+  jselcarithmetic(cinfo);
+#else
+  cinfo->arith_code = FALSE;	/* force Huffman mode */
+#endif
+  jselchuffman(cinfo);
+  /* Pipeline control */
+  jselcpipeline(cinfo);
+  /* Overall control (that's me!) */
+  cinfo->methods->c_per_scan_method_selection = c_per_scan_method_selection;
+}
+
+
+LOCAL void
+initial_setup (compress_info_ptr cinfo)
+/* Do computations that are needed before initial method selection */
+{
+  short ci;
+  jpeg_component_info *compptr;
+
+  /* Compute maximum sampling factors; check factor validity */
+  cinfo->max_h_samp_factor = 1;
+  cinfo->max_v_samp_factor = 1;
+  for (ci = 0; ci < cinfo->num_components; ci++) {
+    compptr = &cinfo->comp_info[ci];
+    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
+	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
+      ERREXIT(cinfo->emethods, "Bogus sampling factors");
+    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
+				   compptr->h_samp_factor);
+    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
+				   compptr->v_samp_factor);
+
+  }
+
+  /* Compute logical subsampled dimensions of components */
+  for (ci = 0; ci < cinfo->num_components; ci++) {
+    compptr = &cinfo->comp_info[ci];
+    compptr->true_comp_width = (cinfo->image_width * compptr->h_samp_factor
+				+ cinfo->max_h_samp_factor - 1)
+				/ cinfo->max_h_samp_factor;
+    compptr->true_comp_height = (cinfo->image_height * compptr->v_samp_factor
+				 + cinfo->max_v_samp_factor - 1)
+				 / cinfo->max_v_samp_factor;
+  }
+}
+
+
+/*
+ * This is the main entry point to the JPEG compressor.
+ */
+
+
+GLOBAL void
+jpeg_compress (compress_info_ptr cinfo)
+{
+  /* Read the input file header: determine image size & component count.
+   * NOTE: the user interface must have initialized the input_init method
+   * pointer (eg, by calling jselrppm) before calling me.
+   * The other file reading methods (get_input_row etc.) were probably
+   * set at the same time, but could be set up by input_init itself,
+   * or by c_ui_method_selection.
+   */
+  (*cinfo->methods->input_init) (cinfo);
+
+  /* Give UI a chance to adjust compression parameters and select */
+  /* output file format based on results of input_init. */
+  (*cinfo->methods->c_ui_method_selection) (cinfo);
+
+  /* Now select methods for compression steps. */
+  initial_setup(cinfo);
+  c_initial_method_selection(cinfo);
+
+  /* Initialize the output file & other modules as needed */
+  /* (entropy_encoder is inited by pipeline controller) */
+
+  (*cinfo->methods->colorin_init) (cinfo);
+  (*cinfo->methods->write_file_header) (cinfo);
+
+  /* And let the pipeline controller do the rest. */
+  (*cinfo->methods->c_pipeline_controller) (cinfo);
+
+  /* Finish output file, release working storage, etc */
+  (*cinfo->methods->write_file_trailer) (cinfo);
+  (*cinfo->methods->colorin_term) (cinfo);
+  (*cinfo->methods->input_term) (cinfo);
+
+  /* My, that was easy, wasn't it? */
+}